The present invention relates generally to operator's cabs mounted on self-propelled crop harvesting machines, such as combines, and, more particularly, to an improved air filtration system that requires the use of a filter cartridge within the filtration chamber to enable the service door to be latched.
Modern self-propelled crop harvesting machines are generally equipped with an enclosed operator's cab in which the operator is seated to control the harvesting operation of the machine. Such operator's cabs are generally provided with environmental controls, such as air conditioning and sound absorbing materials, to improve the quality of work environment for the operator. Operator cabs are generally mounted at an elevated position on the crop harvesting machine to afford the operator a field of view of the harvesting operation relative to the gathering of crop material from the field in which he is operating. To permit this field of view, the cab enclosure is provided with a number of transparent panels, normally glass, supported from vertical posts extending between the floor member and the roof member of the cab. To permit access to the cab, the cab enclosure is provided with an access door pivotally mounted to one of the support posts for movement between closed and opened positions.
Since the cab enclosures are generally sealed to maintain environmental conditions within the cab, it is necessary to provide a system for the inlet of fresh air into the enclosure. Typically, such systems provide an air filtration system to filter dirt and debris from the inlet air and, thereby, keep the interior of the cab enclosure as clean as possible. It would be desirable to provide an inlet air filtration system which would be easy and convenient to service from outside the cab enclosure, that would require the cab door to be closed during service operations, that would provide a visual indication when the filter cartridge is not installed, and that would not require the roof of the operator's cab to be lifted to affect service operations.